Tool mechanism for gear cutting machines



Feb. 21, 1939. 4 H. JOHANSON ET AL ,1 2

TOOL MECHANISM FOR GEAR CUTT ING MACHINES Filed Sept: 25, 1936 4 Sheets-Sheet 1 Feb. 21, 1939. M. H. JoHANsoN ET AL 2,143,072

. TOOL MECHANISM FOR GEAR CUTTING MACHINES Filed Sept. 25, 1936 4 Sheets-Sheet 2 Feb. 21, 1939.

M. H. .JCDHANSON ET AL TOOL MECHANISM FOR GEAR CUTTING MACHINES 4 Sheets-Sheet 3 Filed Sept. 25, 1936 3nnentors @fZe/Z (5. 'Czn '7 (Ittorneg Feb. 21, 1939. M. H. JOHANSON ET AL 2,148,072

TOOL MECHANISM FOR GEAR CUTTING MACHINES Filed se t'. 25, 1936 4 Sheets-Sheet 4 IIIIIH IIIIIIH Patented Feb. 21, 1939 UNITED STATES amen PATENT OFFICE TOOL DIECHANISM FOR GEAR, CUTTING MACHINES York Application September 25, 1936, Serial No. 102,550

6 Claims.

The present invention relates to tool mechanism for gear cutting machines and more particularly to tool mechanism of the reciprocating type in which the tool cuts on its stroke in one direction and is Withdrawn from cutting position at opposite ends of its strokes which will be simple in operation, sturdy in construction, compact, and hold the tool rigidly during cutting.

Another object of the invention is to provide a mechanism for reciprocating a tool at a varying 'velocity so that the return stroke of the tool may be at a faster rate than its cutting stroke in order thereby to reduce the idle time of the machine.

Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims.

In the drawings:

Figure 1 is a partial sectional view of a gear cutting machine of known type provided with a tool mechanism constructed according to a preferred embodiment of the present invention;

Figure 2 is a side. elevation of the tool head of the machine, parts being shown in section;

Figure 3 is a section through the tool head taken. substantially on the line 33 of Fig. 2;

Figure 4 is a plan view of the tool head, show ing the tool in cutting position;

Figure 5 is a diagrammatic view illustrating the operation of the improved tool head;

Figure 6 is a side elevation of the crank-plate for imparting the reciprocating movement to the tool and showing the mechanism for controlling the speed of movement of the tool; and

Figure 7 is a wiring diagram showing the wiring of the motor which drives the crank-plate and actuates the tool mechanism.

The invention is shown as applied to a machine of the type described in the U. S. Patent to Candee and J ohanson, No. 1,616,439, of February 8, 1927. Here the blank has a continuous indexing rotation and the tool is fully relieved from is not indexed until a tooth or tooth space has been completely cut.

In the embodiment of the invention shown, the tool is mounted upon a clapper block which is actuated to impart the relieving movements to the tool. The clapper block is mounted on the tool slide by means of a pair of cranks or eccentrics which are disposed, respectively, on either side of the tool so that when they are rotated at the ends of the strokes of the tool slide they impart a parallelogram motion to the tool to move it to or from cutting position depending upon the direction of their rotation. The tool slide is reciprocated by a crank driven from a variable speed motor and a cam is mounted on the face of the crank plate which operates a limit switch that controls the variable speed motor in such a way that at the end of each cutting stroke of the tool, the motor is speeded up to produce a quick return motion of thetool slide and thereby reduce the idle time of the machine to a minimum. The cranks or eccentrics for operating the clapperblock may be actuated from a cam integral with the crank-plate in a manner similar to the clapper block actuating mechanism shown in the patent mentioned.

Referring to the drawings by numerals of reference, l indicates the upright or frame of a gear cutting machine such as shown in the Candee et al. patent. I I designates the cradle of the machine and I2 the guide or arm for supportingthe tool mechanism. The tool slide is denoted at l4 (Figs. 1, 2 and 3) and is reciprocated through a crank mechanism to impart the cutting and return strokes to the tool.

The driveto the tool slide is from the variable speed motor l through the shaft l6, coupling l1, bevel gearing l8 and I9, shaft 20, bevel gearing 2! and 22, shaft23, bevel gearing 24 and 25, crank-plate 26, crank-pin 21, connecting-rod 28, and. pin 29. The bevel gear 25 is secured to the back of the crank-plate by screws and the crank-pin 21 is adjustable on the face of the crank-plate in known manner by the screw 32.

The cutting tool itself is denoted at T. It is secured by the bolt in a block 36 which is in turn adjustably fastened to the clapper-block 38 by T-bolts 39 which engage in the elongated T-slot 40 formed in the clapper block.

The clapper block 38 in mounted through antifriction bearings 42 and 43, respectively, upon the pins 44 and 45, respectively, of crank members 46 and 41, respectively. The stud or shaft 48 of the crank member 46 is journaled through an antifriction bearing in the capped bearing 52 of the tool head 54.

The stud or pin 55 of the crank member 41 is journaled through the anti-friction bearing 51 in the bearing 58 which is integral with the tool head 54. The crank members 46 and 41 are inverted with reference; to one another as shown in: Fig. 2 and the bearings and 58 for the shafts of these crank members are located below and above the clapper block, respectively. This construction provides the greatest rigidity in. the tool mounting. The bearing 52' is a capped bearing for the sake of convenience in assembling the parts.

The tool head 54 is mountedon the-tool slide I4 for lateral and angular adjustment thereon. It is secured to the tool slide I4 by T-bolts 60 and by T-bolts 6|. The bolts 60 pass: throughv slightly elongated openings 62 in the head 54 and engage in the T-slots 63 formed in the face of the tool slide I4; The bolts EI-pass through..- elongatedv slots 65 in the head 54 and engage-:alsoiin the T-slots63;

The toolhead is adjusted on. the tool slide, to positionthe-tool in accordance withythe-cone dis-- tanceof the gear. to. be cut,.by. loosening thebolts 60 and 6 I. androtating: the. stubshaft 81: (Fig. 2). This shaft carries..a.spur pinion-.Gtwhi'ch: meshes witharack 69. that is. securedby, screws 7H1v to the.

face-of the tool slide I4}.

andi65 to permit of this adjustment. The stud. I2.

is cylindrical and seatsin a. circularv hole'l3; in a plate 14 that is slidably. mounted in a recess 15' .formedin the face OffthBtOOl' slide l4". The plate 14 is held in positiorron thetool slide by the rack 69 which acts as a gib therefor. The slidable mounting of the plate I4 permits ofits movement with the-tool head 54' intlie lateral adjustment'of' the'latter upon the tool slide- I4.

The lateral adjustment of thetool head upon the slide can be made accurately byuse'of the scale 00 which is secured to the face of" the slide by screws III and which reads agai'nsta pointer 82' that is secured to-theplate'u flig; 291. Angular: adjustment of the tool head 54 can be-ma'de accurately by'useiof the rscale inscribedi on:the1face of the head at one" sidethereon as shown in Fig- 2, and which reads against the pointer 84? which: is

secured torthe plate' I4.

The crank. members 49." and 4:13am". oscillated first in OIIB'dirBCtiOIIEaIIdi thenrinlthe'other at'the opposite ends, respectively; ofr the stroke'of? the tool slide tomove the tool fromaand: to; cutting position. The mechanism for: operating the crank members may be similar'to that. employedin the machine of the C.a.ndee-et.al;.patent above mentioned for operating. the." clapper bl'ock. oscillating mechanism shownlin'that patent Such a mechanism is illustrated inr the? drawings-10f the present application;

The crank plate 2 6 is formedwith; a peripheral: cam-groove 8:2. A cam roller 83? engagesdn. this.- grcove;. The cam: rollerr'is secured: to: a. bar 84 which carries arack member 85;. The'rackmember' 8.5 meshesnwithaspur'piniorn 8.6 thati's keyed to: a rotary member; 81 which is connected by a. universal joint 98. with a telescoping: shaft 89; The telescoping shaft islconnected by: a. universal joint 90with a shaft 92that'isgsuitablyrjournaled in a bracket 93 which is secured by screws 95 (Figs. 2 and 3) to the under face of the tool head 54.

A bevel gear 96 which is keyed to the shaft 92 meshes with a bevel gear 91 which is keyed to the shaft 48 of the crank member 46 so that the crank member 46 is oscillated. upon oscillation of the telescoping shaft 89. Likewise there is a bevel gear 98 keyed to the shaft 92 to mesh with a bevel gear 99 which is journaled on a suitable bearing in a. supporting. member I00 which is secured by screws IOI to the bracket 93.

The bevel gear 99 is adapted to be connected to a crank-plate- I05 (Fig; 2). The crank-plate I05 is connected-to thesh'aft 45 of the crank member 41 by-apin" I06and;.block I01, the latter being slidable in a slot I08 formed in the face of the crankplate= I 05..

The opposed faces of the crank plate and of the sleeve portion of the bevel gear 99 are formed with interengaging clutch. teeth. and' the crank-plate I05.- and' bevel-gear 99' may be-rigidly connected together: by drawingupthe bolt I I0. The clutch connectionv between the crank-plate I05. and the bevel gear 99 permits ofadjusting the crank member 41 angularly so that the crank pin- 45 may. occupy the same relativeangulan position with reference tor-the. crank member 4'I v as. does the crank. pin 44;With reference to. its-crank member 46 .whereby the desired parallelogram. motionmay.

beimpartedto the. clapperblock.

The-crankmembers-Mand-41 are-preferably so the. tool. head and tool slide. when the tool. is in.

cutting position. This minimizes any. tendency of the. cutting thrust on the. tool to. move the tool from. cutting position. In addition, a positive stop is provided to securely hold the tool in cutting position against any cutting thrust. This comprises a block II5 which is secured to the front face of the tool head 54 bythe. screws I'I5 (Figz) and-the gib II'I. Thelatter. is secured to the tool head 54' by thescrew I I8.

The block 5 has a plane'side surface H9 at one end which is adapted to engage the-sl'abbedoff plane surface I20 of the clapper-block when the tool is in cutting position as shown in Fig. 4, so that the cutting thrust of the tool may be taken by the block H5. The surface I20 is formed on one side of the bearing formed on the clapper block for the anti-friction bearing 42- and the crank-pin 4'4. The cap-member I 22 for this bearing is shaped as clearly shown in Fig. 4 to'conform to the shape of thebearing itself. It is secured to-the bearing portion-of the clapper. block by screws I232 The cam-track. 82 in: the crank-plate 26 is so formed'that at the endof the cutting stroke of the toohthe crank. members 4B.-and- 41f are rotated in a direction to move the clapper block rearwardly away from the blank to withdraw the tool from cutting position The tool is held in Withdrawn position on the return stroke. At the end of the return stroke, thecrank members 46 and 41' are again actuated and rotated back to original position to return the tool tocutting position.

The movements of the'clapper block are illustrated diagrammatically in Fig. 5. The dotted lines indicate the position of the clapper block atv the end. of a cutting stroke of: the tool. The

full; lines show the position of the clapper block after the crank members 46 and 41. have been rotated to move the tool from cutting position prior to the returnstroke. :t and :0 indicate thecenters of the shafts 48 and 55. 11 and 11/ indicate the centers of the crank pins 44 and 45- when the clapper block is in cutting position. Y and Y indicate the positions of the centers of the crank pins 44 and 55 when the clapper block is in withdrawn position. The arcs I25 and I26 denote the arcs of travel of the centers of the crank pins 44 and 55 in the movement of the clapper block. i

The path of a point of the cutting tool in the movement of the tool from cutting to withdrawn positionis denoted by the arc I28 (Fig. 5). It will be noted that the slabbed-ofl plane surface I20 of the clapper block seats against the end face H9 oi the block H5. in cutting position so that the block II5 may take the cutting thrust on the tool, as above described, but that in the withdrawn position, the surface I20 is clear of the block II5.

For gears of large sizes and long face width, it is especially desirable to speed up as much as possible the idle return movement of the tool so as to minimize as far as possible the idle time of the machine. To this end, we employ a variable speed motor, as stated, for driving the tool crank and provide means for controlling this motor so that while it operates at the necessary slow speed during cutting, it may function at high speed as soon as each cutting stroke is completed to produce a high speed return stroke of the tool.

The control mechanism for the motor includes an arcuate cam-plate I30 (Fig. 6) which is secured to the face of the crank-plate 26 and extends through an arc of The cam-plate is formed with beveled end surfaces I3I and I32.

The cam-plate I30 is adapted to cooperate with a pivoted trip arm I34 that operates a limitswitch I35 through contact with the roller I36 of this switch.

The limit-switch I35 is adapted to control the field rheostat of the drive motor I5 as illustrated diagrammatically in Fig. 7.

AI and A2 denote the main lines to the arma-. ture of the motor and FI and F2, the main lines of the field of the motor. The field rheostat is denoted at I40.

During cutting, the full resistance of the rheostat is used and the field circuit of the motor is from the main line F2 through the line I4I, the rheostat I40, the line I42, line I43, terminal I44 of the motor, terminal I45 01' the motor and line I46 back to the main line FI. is rotating in the direction of the arrow (Figs. 6 and '7) and at the end of the cutting stroke of the tool, the tip of the arm I34 will ride up on the cam I30, closing the limit-switch I35. This will close a circuit from the main line F2 through the limit switch I35, the line I48, the line I49, the coil I50, and line I5I to the main line FI. This will energize the coil I50 and. cause it to close the switch arm I52 of the motor controller. The field circuit of the motor I5 is thus caused to extend from the main line F2 through the line I4I, a limited numberof coils of the rheostat I40 as determined by the setting of the rheostat, the line I54, the switch arm I52 and the line I43, the terminals I44 and I45 of the motor I5, and the line I46 to the main line FI. Thus, the motor will rotate at higher speed, the speed being de termined by the setting of the rheostat, and the crank plate 26 will be driven at higher speed for the return movement of the tool. At the end of the return movement of the tool, the arm I34 will drop off of the cam I30 so that the tool slide The crank plate 26 v will again be driven at slow speed for the cutting movementof the tool.

For gears of short face-width, the speed control mechanism may be rendered inoperative by closing the switch I555 This serves to cut the coil I50 out of the circuit when the limitswitch I35is closed, for current will flow from the line F2 through the line I56, switch I55, lines I51 and I48 and switch I35 back to line F2 rather than through the coil I50.

In the drawings the tool has been shown as cutting from the outer to the inner ends of the teeth of the blank. For cutting in the reverse direction, the tool'is reversed on the tool block and the stop-plate I I 5 is reversed so that the side I I9 of the block will abut against the slabbed-ofi surface I60 of the clapper block to hold the tool against cutting thrusts. The drive to the telescoping shaft 89 from the cam 82 is also reversed as described in Patent No. 1,616,439 so that the tool is moved in the proper direction, to or from cutting position at the ends of its stroke.

While the invention has been described in connection with a machine of a particular type, it will be understood, as previously stated, that the invention is capable of wide use and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice in the gear art and. as may be applied to the essential features hereinbefore set forth and as fall within the scope of the invention or the limits of the appended claims.

Having thus described our invention what we claim is:

1. In a machine for producing gears, a frame, a slide, a support, a cutting tool mounted on one of said parts, a pair of parallel swinging arms, each connected at one end to the support and at its opposite end to one of the two first named parts, means for reciprocating said slide to impart cutting and return movements to the tool, and means for simultaneously imparting motion to the two arms at opposite ends of the stroke of the slide to move the tool to and from cutting position.

2. In a machine for producing gears, a slide, a clapper block, a tool secured to the clapper block, a pair of parallel swinging arms, each connected at one end to the clapper block and at its opposite end to the slide, means for reciprocating the slide to impart cutting and return movements to the tool, and means for simultaneously imparting swinging motion to the two arms at opposite ends of the stroke of the slide to move the tool to and from cutting position.

3. In a machine for producing gears, a slide, a clapper block, a tool secured to the clapper block, a pair of cranks joumaled in the slide and having their pins secured to the clapper block, means for reciprocating the slide to impart cutting and return movements to the tool, and means for oscillating said cranks in opposite directions, respectively, at opposite ends oi. the stroke of the slide to move the tool to and from cutting position.

4. In a machine for producing gears, a slide, a tool block, a tool secured to said block, a pair of parallel arms, each pivotally connected at one end to the slide and each pivo-tally connected at its opposite end to the tool block with the pivotal connections of the two arms to the slide being disposed at opposite sides of the path of cutting travel of the tool, means tor reciprocating said slide to impart cutting and return movements to the tool, and means forsimultaneously swinging the arms in opposite directions at opposite ends, respectively, of the stroke of the slide to move the tool to and from cutting position.

5. In a machine for producing gears, a slide, a tool block, a tool secured to the block, a pair of parallel arms, eachpivotally conected at one end to the slide and each pivotally connected at its opposite end to the tool block, means including a rotary'crank for reciprocating the slide to impart cutting and return movements to the tool, and'means actuated on rotation of the crank for simultaneously oscillating said arms in opposite directions at opposite ends, respectively, of

the stroke of the slide to move the tool to and from cutting position.

6. In a machine for producing gears, a slide, a tool vblock, a tool secured to said block, a pair of parallel arms, each pivotally connected at one end to the slide and each pivotally connectedat its opposite end to the tool block, means including a rotary crank .for reciprocating the slide to impart cutting and return movements to the tool, and a cam secured to the crank and operatively'connected to the .arms to oscillate the arms on rotation of the crank in opposite directions at opposite ends, respectively, of the stroke of the slide to move the tool to andlfrom cuttingrposition.

'MAGNUS H. JOHANSON.

ALBERT E. CLARK. 

